The size, shape and stability of a plant depend on the flexibility and integrity of its cell walls, which, at the same time, need to allow cell expansion for growth, while maintaining mechanical stability. Biomechanical studies largely vanished from the focus of plant science with the rapid progress of genetics and molecular biology since the mid-twentieth century. However, the development of more sensitive measurement tools renewed the interest in plant biomechanics in recent years, not only to understand the fundamental concepts of growth and morphogenesis, but also with regard to economically important areas in agriculture, forestry and the paper industry. Recent advances have clearly demonstrated that mechanical forces play a crucial role in cell and organ morphogenesis, which ultimately define plant morphology. In this article, we will briefly review the available methods to determine the mechanical properties of cell walls, such as atomic force microscopy (AFM) and microindentation assays, and discuss their advantages and disadvantages. But we will focus on a novel methodological approach, called cellular force microscopy (CFM), and its automated successor, real-time CFM (RT-CFM).
In this article, we introduce the real-time cellular force microscope (RT-CFM), a high-throughput microrobotic platform for mechanical stimulation and characterization of single cells. We developed computer vision algorithms that fully automate the positioning of target cells and localization of the sensor tip. The control and acquisition architecture dramatically increases the accuracy, speed, and reliability of force measurements. Pollen tubes provide an ideal model system for the study of plant mechanics at the single-cell level. To quantitatively obtain the physical properties of the plant cell wall, we generated topography and stiffness measurements from 3D scans of living, growing pollen tubes. We report techniques for real-time monitoring and analysis of intracellular calcium fluxes during mechanical intervention. Our platform is compatible with various imaging systems and enables a powerful screening technology to facilitate biomechanical and morphological characterization of developing cells.
We present a microrobotic platform that combines MEMS-based capacitive force sensing technology, a dual-stage positioning system and a real-time control and acquisition architecture with computer vision automation to manipulate and mechanically characterize growing plant cells. The topography accuracy of the system, using a silicon wafer sample is measured to be 28 nm (1σ, 200Hz). With an SI-traceable stiffness reference we estimate the accuracy of the RT-CFM to be 3.49%. The target locations are selected from an interactive image of the workspace, and the sensing tip is positioned at each location using visual servoing techniques. Topography and stiffness maps were successfully obtained on growing pollen tubes. With the proposed system, cells can be mechanically stimulated at high speeds and with high precision while the intracellular components are visualized using confocal imaging. The system offers a versatile solution for dexterous and highthroughput characterization of biological specimen.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.